Rs-422A / Rs-485 Connector - Omron PROFIBUS DP GATEWAY Operation Manual

Unit Components
2-1-5

RS-422A / RS-485 Connector

R-
R+
FG
S-
S+
Address setting
22
The signals DGND and VP are used to power the bus terminator located in
the cable connector.
Note 1. The orientation of the sub-D connector allows the use of PROFIBUS con-
nectors with a 90° angle cable outlet, e.g ERNI, Delconec and Phoenix.
2. The 9-pin sub-D connector uses #4/40 UNC thread for mechanical fixation
of the cable connector. Make sure that if non-standard PROFIBUS connec-
tors are used, the same thread is used on the cable connector.
3. PROFIBUS DP Baud rate setting is accomplished through automatic de-
tection, all the defined PROFIBUS DP baud rate values are supported.
The RS-422A / RS-485 port is a dedicated RS-422A / RS-485 compliant inter-
face, which is galvanically isolated. The PRT1-SCU11 has a switch on the
front case, allowing the user to select either the RS-422A or the RS-485 phys-
ical layer. The Unit also provides a switch to turn a 220 Ohm termination resis-
tor ON or OFF The termination resistor is placed inside the Unit and between
the two receiver lines of either RS-422A or RS-485.
Pin No.
R- RD- Receiver line
R+ RD+ Receiver line
FG Frame Ground
S- SD- Transmission line
S+ SD+ Transmission line
Note In case Switch 1 is set to ON and RS-485 is selected, the A and B lines are
doubled on the S-/S+ connector pins, i.e. the signal on R- is the same signal
as on S- and the signal on R+ is the same signal as on S+.
The communication through the RS-422A / RS-485 interface does not require
a separate address setting feature. All connected devices must have
addresses selected in the range of 1 through 15. The address set on the
device must match the slot number of the selected PROFIBUS I/O-module.
Free Communication Blocks carry their own address as part of the message
itself.
The default communication format used on the RS-422A / RS-485 interface
depends on whether Memobus or one of the other protocols will be used, i.e.
it depends on the setting of DIP-switch 3. The table below lists the default
communication settings used.
Format
Data length
Stop bit length
Error detection
Description
RS-422A (Switch1 OFF)
Memobus
(DIP-Switch 3 ON)
8 bits 7 bits
1 bits 2 bits
1 bit, even parity 1 bit, even parity
Section 2-1
RS-485 (Switch 1 ON)
A line Transmit/Receive line
B line Transmit/Receive line
Frame Ground
A line Transmit/Receive line
B line Transmit/Receive line
Compoway-F / Host Link / K-Format
(DIP-switch 3 OFF)